On the weekend America remembered the victims of the worst terrorist attack in U.S. history, President Bush also paid his respects to the hundreds of lives lost earlier this month at a school in southern Russia.

The president went to the Russian embassy in Washington Sunday to sign a condolence book, and express his sympathy "The atrocities that took place in the school were beyond comprehension. Many in America and I know many in Russia simply cannot conceive the heart of a person who would mow down innocent children," he said.

The visit by the president and first lady Laura Bush was not listed on his official schedule, and took White House reporters by surprise. But it was broadcast live across Russia. Mr. Bush, speaking in somber tones, delivered a brief statement of unity in trying times.

"The United States stands side by side with Russia as we fight off terrorism, as we stand shoulder to shoulder to make the world a more peaceful place," he said.

Mr. Bush referred to those behind the attack "as evil terrorists." Their target was a school on the first day of classes. Children were taken hostage and the siege lasted for more than 50 hours before it ended September 3 in a nightmare of gunfire and explosions.

The school was located in the town of Beslan, in a region bordering Chechnya. Russian officials say Chechen rebels were behind the hostage-taking and Moscow has vowed to strike militant bases abroad.